Time: 3 ms (99.62%), Space: 20.1 MB (57.74%) - LeetHub

0385-mini-parser/0385-mini-parser.py

@@ -0,0 +1,84 @@
+# """
+# This is the interface that allows for creating nested lists.
+# You should not implement it, or speculate about its implementation
+# """
+#class NestedInteger:
+#    def __init__(self, value=None):
+#        """
+#        If value is not specified, initializes an empty list.
+#        Otherwise initializes a single integer equal to value.
+#        """
+#
+#    def isInteger(self):
+#        """
+#        @return True if this NestedInteger holds a single integer, rather than a nested list.
+#        :rtype bool
+#        """
+#
+#    def add(self, elem):
+#        """
+#        Set this NestedInteger to hold a nested list and adds a nested integer elem to it.
+#        :rtype void
+#        """
+#
+#    def setInteger(self, value):
+#        """
+#        Set this NestedInteger to hold a single integer equal to value.
+#        :rtype void
+#        """
+#
+#    def getInteger(self):
+#        """
+#        @return the single integer that this NestedInteger holds, if it holds a single integer
+#        Return None if this NestedInteger holds a nested list
+#        :rtype int
+#        """
+#
+#    def getList(self):
+#        """
+#        @return the nested list that this NestedInteger holds, if it holds a nested list
+#        Return None if this NestedInteger holds a single integer
+#        :rtype List[NestedInteger]
+#        """
+
+class Solution:
+    def deserialize(self, s: str) -> NestedInteger:
+        """
+        Complexities:
+        Time: O(n)
+        Space: O(n)
+
+        where n = len(s)
+        """
+
+        # base case: number
+        if s[0] != "[":
+            return NestedInteger(int(s))
+
+        # is a list
+        head = NestedInteger()
+        stack = [head]
+
+        i = 1
+        while i < len(s):
+            if s[i] == ",":
+                i += 1
+            elif s[i] == "[":
+                newNestedInteger = NestedInteger()
+                stack[-1].add(newNestedInteger)
+                stack.append(newNestedInteger)
+                i += 1
+            elif s[i] == "]":
+                stack.pop()
+                i += 1
+            else: # Is number or '-'
+                # Find entire number
+                j = i
+                while s[j] not in ",]":
+                    j += 1
+                newInt = int(s[i:j])
+                stack[-1].add(NestedInteger(newInt))
+                i = j
+
+        return head
+